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Finding the Fourth Proportional to 427.57, 641.21 and 138.94

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Solution

The fourth proportional to 427.57, 641.21 and 138.94 is: 208.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.57 : 641.21 = 138.94 : x
  2. Step 2: Convert to fraction form
    427.57/641.21 = 138.94/x
  3. Step 3: Cross multiply
    427.57x = 641.21 × 138.94
  4. Step 4: Simplify right side
    427.57x = 89,087.94
  5. Step 5: Solve for x
    x = 89,087.94/427.57
  6. Step 6: Final answer
    x = 208.36

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.